Integrated Carbon Dioxide Capture and Electrochemical Conversion: Chemistry, Electrode and Electrolyzer Design, and Economic Viability

Abstract

Electrochemical carbon dioxide (CO₂) conversion (ECC) offers a promising route to reduce CO₂ emissions and to store renewable electricity in the form of chemical fuels. To date, ECC has been mainly based on pure CO₂ gas isolated from carbon capture solutions, which is an energy-intensive step. Recently, direct CO₂ conversion from a capture solution, which enables integrated CO₂ capture and electrochemical conversion, has attracted attention because it can eliminate the energy-intensive CO₂ isolation step. In addition, producing concentrated gas products in integrated systems reduces the cost for downstream separation. This review discusses the key aspects of integrated CO₂ capture and electrochemical conversion systems, including direct air capture (DAC), the chemistry of CO₂ capture and release, electrode designs and system configurations, as well as technoeconomic viability. First, the fundamental concepts and chemistry of CO₂ capture and in situ CO₂ release in electrochemical reactors are summarized. Then, recent advancements in integrated systems are discussed, covering both system configurations and electrode designs. Potential avenues for enhancing product selectivity toward high-value chemicals, such as ethylene and ethanol, as well as lowering operating cell voltages and improving the economic viability of integrated systems, are highlighted. Finally, major technical and economic challenges as well as emerging research opportunities in the domain of integrated CO₂ capture and conversion are highlighted.